Sample meal preparation
All the raw plant materials were placed in a freezer at
-20°C, cut into chips (ca. 25 × 6 × 3 mm) and freeze-dried.
After freeze-drying, the chips were ground into meal in a
Wiley mill (Retsch cutting mill SM 1). The sample meal
was sieved and 250-500-μm particles were collected. The
completely processed sample meal was then placed in a
freezer at -20°C. Voucher specimens were deposited in the
Division of Bio-resource, Paper and Coatings Technology,
Universiti Sains Malaysia (USM).